A British tourist has appeared before an Australian court accused of swallowing a stolen, rare diamond worth more than £100,000.

Matthew Mark Luke John Osborne was arrested by police at Melbourne's Tullamarine Airport as he attempted to board a New Zealand-bound flight on Thursday.

He was also X-rayed by officers to determine whether he had ingested the gem.

The 29-year-old was flown to Cairns the next day.

The pink Argyle diamond was stolen from the Diamond Gallery in Cairns on February 15 as it was being shown to a male customer who fled the store on a mountain bike.

The shop's owner Keith Bird said the diamond was so small that it could easily be hidden.

"That's the big mystery, we still don't know, but we're hoping. It's being so small, it's 4.3 millimetres (0.17 inches) in diameter. So I've heard of women secreting them in face creme and all sorts of places."

Police said the X-rays were "inconclusive" and that the gem was "still outstanding" and investigations were continuing.